Spark plug



Feb. 12 1924.

E. OCONNELL SPARK PLUG Filed Aug. 30. 1920 Patented Feb. 12, 1924.

UNITED STATES EDWARD 6CONNELL, OF PHILADELPHIA, PENNSYLVAK SPARK PLUG.

Application filed Augult 80, 1920. Serial No. 408,855.

To all whom it may concem:

Be it known that I, EDWARD OCoNNnm, a citizen of the United States residing at Philadelphia, in the county of lhiladel hm and State of Pennsylvania, have invented certain new and useful Improvements in Spark Plugs, of which the following 15 a specification.

My invention relates to improvements in electrical igniters having a take-apart con struction, the common name for igmters being spark plugs; and the objects of my mvention are, first, to provide a self-contained means for ridding the igniter of carbon and other foreign accumulatlons without removing it from the cylinder head of the engine and second, to afford facilities for ad'ustmg the electrodes one with another to orm a spark gap and locking the electrodes into any determined ad'ustment, the locking means rendering suc adjustment normally constant, and being capable of restoring the predetermined relation of the electrodes should the adjustment therebetween be disturbed.

I have attained these objects and other objects and advantages which will become apparent from the description to follow and will be specifically pointed out and referred to in the claims appended, by the mechanism illustrated in the accompanying drawings in which Figure 1 is a side elevation of my device;

Figure 2 is a longitudinal section thereof;

Figure 3 is a bottom plan view;

Figure 4 is a sectional view on the line 4--4 of Fig. 2 looking in the direction of the arrows; and

Figure 5 is a perspective view of the terminal electrode used therein.

Similar numerals refer to similar parts throughout the several views.

In my igniter, I employ a rounded terminal electrode A of suitable material, the stem 1 thereof being slightly reduced at its uppermost end, the reduced portion 1 being knurled or roughened that a firm grasp of the electrode between the thumb and fingers may be obtained. Adjacent to the reduced ortion, the stem is threaded, the threads Being indicated by the numeral 2 and being of a size suitable to receive any standardv size thumb screw, the thumb screw 3 which I prefer, being counter bored at 4 to facilitate its placement upon the stem.

The lower part 5 of the electrode is lar er than the stem, a shoulder 6 substantis ly perpendicular to the axis of the electrode being formed between the stem and the enlarged part. Aflixed to the extremity of the latter y riveting 7, or b. other suitable means, 1s a disk 8 preferably circular and having peripheral projections 9.

For insulation, I employ a core B of porcelain or other suitable non-conductin rial, the lower portion 10 thereof being enlarged forming the shoulder 11. The core is longitudinally bored in the usual manner, indicated by 12 to receive the stem 1 which should fit snugly but not so closely that it can not be readily moved up and down and rotated when grasped between the thumb and fingers at 1'.

Resting upon shoulder 6 of the electrode A is a washer or collar 13 composed of either metallic or non-metallic material and of suitable diameter to form rotective packing for the lowermost sur ace of the core B against which it rests, while the uppermost surface of said core is covered-by a cap 14 having a depending rim 15 fitting closely about the periphery of the core.

Core B is snugly seated in a shell C, said shell having a depending apron 16 within which is the plug firing chamber, external shoulder 17 and internal shoulder 18 being intermediate the shell and the apron. Externally, the shell has a number of angular faced surfaces 19 to receive a wrench or other suitable tool while the apron is provided with coarse threads 20 for engagement with the cylinder head of the engine, shoulder 17 of the igniter engaging with the cylinder wall when the former is screwed into position to seal the crevice between the two.

Projecting inwardly of the apron are the depending arms 21 of apron 16 supporting an annular electrode 22 to receive the ground current, the electrode being of substantially the same diameter as the disk 8. v

The shell C is internally threaded as indimate as cated at 23 to receive a jam nut D, said nut having threads 24.- for engagement with the shell, and to facilitate the posltiomn thereof, a number of angular faces 25 ermin a Wrench hold are provided. Jam nut 15 by ressure a ainst shoulder 11 of the core B fdrces the atter into proper position in the shell (1, and maintains it in such position tightly sealing the crevice between the core and shell.

From the brief description of the parts which I have given their purpose is apparent, nevertheless to outline the advantages of my igniter it will be necessary to describe in a limited manner some of the functions each part thereof possesses. To assemble, thumb nut 3 is removed from the electrode A, the washer 13 placed upon the shoulder 6, and the stem I inserted into bore 12 of the core B, the cap 14 then being dropped into place u on the latter. The core is then seated in t e shell G, the jam nut D forced against the shoulder 11 of the core and screwed tight to secure the latter in place, the shell inserted into the cylinder head of an engine, the terminal E of a conduit from the current supplying means placed around stem 1 and upon the cap 14, thumb nut 3 then being screwed into position to complete the assembly. It is apparent that by tightening jam nut D or thumb screw 3, any looseness of the parts may be overcome and the plug made leak proof. At the same time it is clear that each part of the igniter is always independent of the other parts and ma be removed for replacement, and replaced y a new part with the aid of no tool other than a wrench.

Current passing into electrode A from terminal E jumps to the annular electrode 22 of shell C carrying the ground current formin a fan flame spark, a form of spark especia ly desirable for gas engine ignition. The projections 9 in disk 8 materially promote the production of a spark of this type.

From prolonged use, accumulations of carbon and other foreign matters may form within the apron 16 and about the electrodes 8 and 22, such accumulations tending to produce short circuits. To dislodge accumulations choking the space interme-' diate the apron and the terminal electrode it is but necessary to loosen up thumb nut 3 and move the electrode A up and down while the two electrodes may be cleaned and brightened by rotation of the terminal electrode while pressing it downwardly against the ground electrode. The projections in the periphery of the disk electrode, of course, materially assist in the cleansingaand polishing operation just described. eplacement of the thumb nut restores the electrode to their previous adjustment.

Protection in the core B is afforded by the cap 14 which completely covers the top surface and surrounds the uppermost portion thereof while the shell G covers the major portion of the side of core and a. portion of its lower surface, an additional portion of such lower surface being protected by the washer 13 which also serves as a packing.

The protective Washer 13 has an fiddle tional function, that of providing means for adjustment of the spark gap between the two electrodes. A narrow washer will cause a wide gap to be formed therebetween while a wider washer will reduce the spark gap hence the i iter is possessed of means for complete a justment. It is apparent that by this means the spark gap may be predetermined, and when once fixed is maintained by the thumb nut 3 which when tightened locks the electrodes into spaced relation one with another and provides a means whereby, should the adjustment between the electrodes become disturbed, reestablishment of the predetermined relation is at once obtainable. This feature is not tobe lightly considered, especially when so much engine trouble is caused by novices meddlin with the ignition system, for the device have invented renders the igniter, the all important part of the igniter system, proof against damage or destructive derangement in the hands of the inexperienced. v

Bearing in mind that sturdiness of parts brings strength and durability as well as long life, and results in economy," I have designed my igniter without small or readily broken parts, and have produced a device which can be manufactured cheaply because of its simplicity and because none of its parts require fine mechanical skill for prouction or assembly.

While the preferred embodiment of my device is depicted in the accompanyin drawing, I do not limit myself to the specific construction shown therein for modifications and changes within the scope of the claims are contemplated and are to be resorted to when desired.

What I claim as new and desire to secure by Letters Patent is 1. A spark plug, including a shell, a fiat ring shaped electrode carried thereby, a disc electrode arranged in a spaced and parallel relation with the ring electrode and having laterally projecting teeth at its periphery which overhang the ring shaped electrode, and a stem carrying the disc electrode, said stem being slidable and rotatable to bring the disc electrode into engagement with the ring electrode and rotate it While in such engagement, the lateral teeth of the disk electrode then sweeping over the face of the ring electrode.

2. A spark plug having an annular ground electrode extending inwardly of its lower .end, an insulating core fixedly disposed in said plug, a stem having ,a shoulder intermediate its lenh slidably mounted in said being movable toward or from the round core, seid stem l eving at its lower end a disk electrode, and a binding nut threade upon electrode, such disk being provided with the upper end of the stem and locking the 1 peripheral projections, a washer disposed washer in coecting relation to the core.

6 upon said shoulder c'oacting with the core to In testimony whereof I aflix my signature.

predetermine the normal spaced relation of the electrodes the lower end of said stem EDWARD OCONNELL. 

